import sys
def rs(): return sys.stdin.readline().rstrip()
def ri(): return int(rs())
def rs_(): return [_ for _ in rs().split()]
def ri_(): return [int(_) for _ in rs().split()]

X = ri()
print('Yes' if X >= 30 else 'No') import sys sys def rs(): return sys.stdin.readline().rstrip() rs def ri(): return int(rs()) ri _ for _ in rs().split() for _ in rs().split() _ rs().split() ().split () rs split for _ in rs().split() _ def rs_(): return [_ for _ in rs().split()] rs_ int(_) for _ in rs().split() for _ in rs().split() _ rs().split() ().split () rs split for _ in rs().split() int(_) int _ def ri_(): return [int(_) for _ in rs().split()] ri_ X = ri() X ri() ri print('Yes' if X >= 30 else 'No') print 'Yes' if X >= 30 else 'No' X >= 30 X 30 'Yes' 'No' def rs(): return sys.stdin.readline().rstrip() def rs(): return sys.stdin.readline().rstrip() rs def ri_(): return [int(_) for _ in rs().split()] def ri_(): return [int(_) for _ in rs().split()] ri_ X = ri() ri() X def ri(): return int(rs()) def ri(): return int(rs()) ri def rs_(): return [_ for _ in rs().split()] def rs_(): return [_ for _ in rs().split()] rs_
import sys
def rs(): return sys.stdin.readline().rstrip()
def ri(): return int(rs())
def rs_(): return [_ for _ in rs().split()]
def ri_(): return [int(_) for _ in rs().split()]

X = ri()
print('Yes' if X >= 30 else 'No')